


lepidopterology and other fields of study

by KuroFae



Category: Welcome to Night Vale
Genre: 3+1 Things, Autistic Carlos (Welcome to Night Vale), Cecil is Mostly Human, Cuddling & Snuggling, Established Relationship, Fluff, Implied Sexual Content, Implied/Referenced Sex, Jargon, Kissing, M/M, Making Out, Medical Jargon, Non-Sexual Intimacy, POCecil, Science
Language: English
Status: Completed
Published: 2020-03-19
Updated: 2020-03-19
Packaged: 2021-02-28 20:47:40
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,085
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23213512
Author URL: https://archiveofourown.org/users/KuroFae/pseuds/KuroFae
Summary: He thinks of Cecil’s breath ghosting over his mouth, and how the oxygen exhaled along with the carbon dioxide traveled into his own lungs, and how it is possibly incorporated into the molecular structure of any organic compound in his entire body. How molecules that were once a part of Cecil could now be a part of him. How the erythrocytes synthesized in the deepest, most intimate places of his marrow may be built with atoms that mingled with the molecular byproducts of Cecil’s cellular respiration.Or: Carlos spends a lot of time thinking about diffusion.
Relationships: Carlos/Cecil Palmer
Comments: 25
Kudos: 162





	lepidopterology and other fields of study

**Author's Note:**

  * Inspired by [a love song for schrödinger](https://archiveofourown.org/works/886668) by [patho (ghostsoldier)](https://archiveofourown.org/users/ghostsoldier/pseuds/patho). 



> Patho had a couple incredible lines in "a love song for schrödinger" about Carlos finding beauty in sharing the molecular aspects of breath, and I was immediately consumed by the idea. I've since seen the same sentiment in some other fic, but that was the first!
> 
> [Here's an image with layman's terms for the technical jargon I used.](https://cdn.discordapp.com/attachments/642851176957607937/690151887743615043/scientific_terms.png) If I missed anything, please mention it in a comment or message me and I'll clear it up for you! I'm trying to walk the line between scientifically specific and still readable to people who haven't taken post-secondary physiology.

Some indeterminate point after their first date, Carlos kisses Cecil again. It’s different, and it’s absolutely the same. 

Different, in that Cecil is pressed down into the couch under him. There’s a searing line of heat across his front wherever their bodies touch, and the jut of Cecil’s iliac crest is pressing into the soft give of his abdomen. There are fingers in his hair, the close-cropped nails scratching dully at his scalp whenever he runs his tongue over Cecil’s palatine raphe. It’s different in that there is so much more contact, in that he gets to hear Cecil’s groans and breathy little gasps, in that he now knows what it feels like to have Cecil’s tongue run over his molars and catch on his bicuspids.

Same, in that when they finally break to breathe, Cecil’s hot breath spills along Carlos’ chin and Carlos is struck with the thought that the molecules exhaled from Cecil’s lungs have known the smallest unicellular-diameter capillaries of his body. All he can think about is how the space in Cecil’s apartment was once simply air, and has now become more with the diffusion of carbon dioxide and ketones and VOCs expelled from Cecil’s lungs as he pants, chest heaving. All he can think about is that the space has slowly come to have known Cecil at a microscopic level; at an _atomic_ level. And then not slowly at all, Carlos realizes that what he is inhaling is, in turn, no longer simply air. He thinks of oxygen from Cecil’s lungs pouring down his trachea and diffusing across his alveolar membranes, diffusing into his capillaries and being enveloped by hemoglobin; circulating back through his pulmonary veins and his heart and his body before cellular respiration changes it to carbon dioxide and partial pressures force it to diffuse once again, back out of his capillaries and out into the no-longer-simply-air that surrounds them. 

Same as the first time, Carlos is entirely overwhelmed by the spiraling tour of the cardiovascular and respiratory systems his mind takes. Different from the first time, he doesn’t leave; doesn’t have a town to save, and Cecil surges up to press their mouths together once more. 

Carlos is still a bit shell-shocked, spilling out of his skin a bit with these realizations. He can feel himself shaking, his hands trembling from where they’re tucked under his own chest and spread against Cecil’s. He moves away to mouth over Cecil’s jugular so that his shaking doesn’t force their teeth to clack together, and Cecil _keens_ and rolls his hips up into the give of Carlos’ stomach.

Carlos stops thinking about respiratory physiology.

***

He spends a lot of time after, however, thinking about diffusion.

It’s not a difficult concept, nor a particularly interesting one, but it is essential and makes up the basics of physiological function. Which means, in part, that it _is_ interesting to Carlos. Or rather, it was interesting, and now it is of an all-encompassing importance. It’s consuming him entirely.

He’s driving down route 800 with a centrifuge strapped down in the backseat of his coupe, because sometimes samples in Night Vale refuse to stay corporeal long enough to be taken back to his lab, and maybe if he extracts DNA on site it’ll work. He should be worrying about the bumps in the road and the thousands of dollars of laboratory equipment rattling right along with the resonance of the tires on the pavement, but all he can think about is the sand blowing out around the edge of the road and being flung into the sky by speeding traffic. To the naked eye it is a plume, but Carlos can almost See, in the way that Cecil Sees and doesn’t _see_ , each individual grain of sand, ground to a fine powder, suspended in the air. He can imagine the particles mixing with the air molecules, spreading out further over the scrublands bordering the highway. It’s not truly diffusion, the particles are too big, but Carlos stares out over the horizon and thinks of sand suspended in the air. He thinks of sand sticking to his lips and his eyelashes and the planes of his face. He thinks of Cecil kissing it off. He thinks of Cecil’s breath ghosting over his mouth, and how the oxygen exhaled along with the carbon dioxide traveled into his own lungs, and how it is possibly incorporated into the molecular structure of any organic compound in his entire body. How molecules that were once a part of Cecil could now be a part of him. How the erythrocytes synthesized in the deepest, most intimate places of his marrow may be built with atoms that mingled with the molecular byproducts of Cecil’s cellular respiration. How the subatomic grains of sand that make up the desert of Cecil’s body may be nestled in every crook and cranny of his own.

Then he thinks about driving, for a bit, because it all becomes a bit too much.

***

At first, the notion is consuming on a physical level. A sexual level. There is something absolutely intoxicating in the idea of exchanging molecules with Cecil. Carlos is no psychologist, but he doesn’t have to be to see he’s toeing a line into some Freudian school of thought. He also doesn’t care much. It’s hard to, when Cecil’s as pent up as he is - _more_ pent up than he is, Cecil’s been waiting quite a bit longer than him - and Carlos can manhandle his lanky form up against the nearest wall and have fingers in his mouth and a hot hand between his thighs in minutes.

The heat tempers with time, though. It doesn’t cool, doesn’t taper off - but the rolling boil settles to a simmer. The steam never stops rising, mixing and dispersing through the air.

He gives Cecil the only functioning watch in Night Vale for their one month anniversary. Cecil gushes over it for far too long, especially given that it is entirely useless due to time refusing to work properly. He has Carlos buckle it onto his left wrist immediately, and wears it with the face on the inside of his wrist, nestled over his ulnar and radial arteries. The silver glints attractively against his desert-dark skin, and Carlos impulsively brings Cecil’s hand up to his mouth to kiss gently below the curve of the watch face. Cecil’s face performs a ballet through several varieties of besotted delight before settling, his eyes half-lidded and his lower lip pulled under his incisors. Carlos pauses to watch him with his lips still pressed to his skin, feeling the quick _thud thud thud_ of his pulse. Carlos inhales through his nose, still watching the fluttering of Cecil’s eyelashes behind his glasses, and is nearly overwhelmed with the sudden scent of Cecil’s cologne flooding over his olfactory nerves. It’s something mellow and velvet, and Carlos is no chemist, not based on his degrees, but in that moment he feels the need to name the compounds responsible for those scents, to name _Cecil_ , with an ache lodged deep in his gut.

He thinks of olfactory neurons and ligand-gated ion channels; of neurotransmission. He traces the path of the electric current Cecil’s cologne sets in motion in his mind’s eye, from the surface of Cecil’s skin to the deepest sections of his own brain. He thinks of molecules, of ions, of diffusion, all a whirlwind of imperceptible activity in the center of his own consciousness. He thinks of how that flurry of activity translates directly to the inscription of Cecil’s cologne deep into his memory, like a chisel to stone. Like the smallest details of Cecil are carved into the deepest recess of the sulci of his mind.

It’s at that moment, crouching on the floor next to the couch and pondering his own sense of smell, that Carlos realizes his fascination is no longer concerned with the physical, but with the knowing.

“Beautiful, perfect Carlos,” Cecil says, and uses his right hand to pull Carlos up to his eye level.

Carlos stares at Cecil’s eyelids - not his eyes, never anyone’s eyes - with a focused intensity he has only ever felt for particle physics. 

“Knowing you in the way I do; being here with you; is a scientifically unlikely outcome. I don’t take it for granted,” Carlos says. It’s not really a reply. Cecil grins sweetly up at him.

“I love you, too,” Cecil says, and kisses him.

***

Cecil twists to face him so that their noses rest with less than a inch of space between them on the pillow they’re sharing. Carlos smiles softly and watches Cecil’s eyes crinkle up as he smiles back. A hand, dark in the low light of their bedroom and adorned with a handsome silver-faced watch, reaches up and tucks a stray lock of Carlos’ hair behind his ear, and Cecil hums in approval once it is tamed and held in place. Carlos hums back, and lets his eyes drift back shut as Cecil scratches along his scalp. He has shivers, in the way that happens when something feels particularly nice. Cecil continues for a couple minutes, and Carlos hums encouragingly every once in a while, just focusing on the points of contact with Cecil’s body, preoccupied with the two paper thin layers of epidermis separating their bloodstreams. If he focuses, he can feel Cecil’s pulse along his femoral artery where their legs are tangled together, and as his own heartbeats slow to match it, he can imagine that Cecil’s heart is circulating blood for both of them. He dwells on this for a moment, but decides there are much more concrete, real, scientific ways to dwell on their closeness, and returns again to diffusion and the sensation of Cecil’s morning breath circulating across the stubble on his own face.

“Carlos,” Cecil breathes across their pillow. His voice is rough from sleep.

“Cecil,” Carlos intones back, and his voice cracks.

“Caramel talker, you,” Cecil teases, but Carlos knows he likes the sound of his name on his lips. “Can I ask you a question?”

“I love questions,” Carlos responds. It’s his response every time Cecil asks this. Cecil keeps asking, so Carlos keeps answering. 

(The first time, they were seated in a corner booth at Rico’s at 9:30 in the evening on a Saturday. The light above their booth flickered out every few seconds, and each time it came back on with a soft click and a hum Carlos could see Cecil’s shadow jump back into place just a half second too late.

“Can I ask you a question?” Cecil asked, and then licked a drop of grease from his slice of Rico’s off of his thumb.

“I love questions,” Carlos said back, still picking scorpion legs off of his own slice, “Hypotheses, at their core, are questions. Without questions we can’t find any answers. And science is all about finding answers.”

It isn’t entirely true. Sometimes science is about finding knowledge for the sake of knowledge, even if you don’t know what to do with the information you find. Carlos thought of lepidopterology and Rh disease and the inherent benefit of the pursuit of knowledge. 

“What are you thinking about right now?” Cecil asked. And so Carlos told him the story of butterfly wings and lives of babies saved, and didn’t realize until much later that Cecil fell just a little bit more in love with every word.)

“What are you thinking about right now?” Cecil asks, still not deviating from this routine. 

Carlos is not thinking about Sir Cyril Clarke, or medical history, or the bone-deep itch of his love for basic research this time. He’s not quite thinking about anything, besides the rise and fall of Cecil’s chest along with his own, and the diffusion of their respective metabolic byproducts into the air around them. He hums once more and Cecil’s nails hit a particularly nice spot on his scalp.

“You,” Carlos answers, and it’s most of the truth.

Cecil chuckles, and Carlos suppresses a shiver as the _huff_ of his laugh slides over his nose, his mouth.

“You bite your lip when you think of science things, you know,” Cecil says through his grin, “That’s why I keep asking - because you keep answering, and you know how I like it when you talk _science_.”

It’s a statement and not a question, meaning he not only suspects, but knows that Carlos has a tell. A tell for science. Carlos’ brain spirals off into the statistics of how many times Cecil must have noticed this correlation to make his data scientifically valid, before he realizes that he’s doing it now. His bottom lip is trapped under the enamel of his incisors. He stops, and runs his tongue along the indent left behind. He can’t hear Cecil laugh, but he feels it in the disruption of the air and the rumble in his chest.

“Am I really that scientifically interesting?” Cecil continues, and stops scratching Carlos’ scalp to run his hand firmly down his shoulder and around his bicep. He starts to say something else, but cuts himself off, and Carlos opens his eyes again to see that Cecil’s pupils are stretched wide, nearly eclipsing his irises. He looks a little awed, but his eyebrows are drawing together, just barely. It’s only because Carlos has catalogued the expressions of his face with high degrees of both precision and accuracy that he can determine the look as vulnerable.

“Of course you are,” Carlos whispers, and runs his hand along the warm, smooth planes of Cecil’s back. Cecil’s eyes flutter and his grip on Carlos’ arm tightens. 

“Am I-” He cuts himself off again. Carlos has rarely seen Cecil struggle with words. His voice drops down to a whisper, like what he has to ask is too intimate to be spoken aloud, even in their empty apartment. “Am I as interesting as everything else in Night Vale?”

_Does your drive to discover; to know; to understand; apply to me?_

_Am I worthy of your devotion?_

“Oh, _Cecil_ ,” Carlos breathes, and digs the tips of his fingers into the tissue protecting the fibres of Cecil’s left trapezius, “I think you are _fascinating_.”

Cecil’s breath shudders, inconsistent, against the sensitive skin on Carlos’ cheek when he exhales, and Carlos shifts his hand to the back of his head and pulls their foreheads to rest together. 

“You know I’m not the one who’s good with words,” Carlos whispers to him, “But I can try. Do you want me to rhapsodize about your biology; your physiology? I could spend the whole day, tens of days, actually, recounting to you the systems of your body, and the tissues that compose them, and the cells that compose those tissues. I can tell you about the molecules that make up the basic unit of your life, and the atoms that make up those molecules. I can tell you about the electrons that circle the nuclei of your being, and of the quarks that make up those nuclei. I can only wonder, of course, where they have been before they were you.

“How do you explain the interconnectedness of all things when you can't even fully comprehend it? Our brains haven’t evolved to grasp the concept of how deep our existence is. We are made up of molecules that have existed since the universe began. There are long-dead stars in your bones, Cecil. All the carbon that composes you could have come from anywhere. I wish we had a way to know. I want to know your story, and all the stories that have come together to let you _have_ a story. I think sometimes, that maybe the molecules that travel through your body know them. Maybe the oxygen that travels through the capillaries in your nephrons changes shape in some way I can’t possibly comprehend. When it is expelled from your lungs into the air around us and I inhale, and that molecule is incorporated into my own blood, do my cells learn its history? Am I really so lucky that I get to know you that completely?”

Carlos swallows, inhales, and then opens his mouth to continue. Closes it again.

The silence hangs heavy over them like a duvet, settling thick and warm over their bodies, isolating the world down to the weight of their bodies against each other and the gentle rasp of their shared breath. It only lasts for a few seconds, or a minute. Or two. It isn’t an eternity, even though it feels like one. Or, maybe it is. Time doesn’t work in Night Vale, but it seems to cooperate whenever Cecil needs respite; needs a reprieve. Carlos waits, for however long it is and however long it might be, and keeps a steady hand on Cecil as he trembles.

“Oh,” Cecil finally says, eloquently. It’s not a remark of awe, or surprise, or anything of that ilk - it’s a noise of confirmation. A noise of acknowledgement, where something one already knows is confirmed by a second party, and only then does the understanding come into the consciousness. Cecil already knows the answer to every insecurity he has regarding Carlos. Sometimes, it needs to be said anyways.

“Oh,” agrees Carlos. 

He rubs circles into the taut suboccipital muscles under the curve of Cecil’s skull, trying to coax the tension from a desk job out of them. Cecil stays where he is, and allows the moment of calm to continue. He hums, and readjusts so his arm is wrapped securely around Carlos’ waist.

Later, after another aeon passes, he will pull away from Carlos, and his hands will be blurs of motion as he gushes, saying ‘that was the most romantic thing that had ever been said to me!’ And Carlos will surge forwards to follow him, meeting his earnestness, with ‘you really mean it, sweetheart?’ And Cecil will nod emphatically, and say something impossibly profound about relationships and existence under the cosmos and the inevitability of eternity, and Carlos will listen and wish he had a pen to commit those words to history. Cecil will laugh, and kiss him. Carlos will kiss him back. Cecil won’t be able to stop grinning, and the kiss will be too much teeth, as it so often is with them. Carlos will try to fix this, and the kiss will be mostly tongue, as it so often is with them. Cecil will pull back, laughing; his breath exhaled directly over Carlos’ mouth.

Carlos will think of diffusion.


End file.
